Gemifloxacin [(R,S)-7-(3-aminomethyl-4-methoxyiminopyrrolidin-1-yl)-1-cyclopropyl-6-fluoro-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carboxylic acid] is a fluoroquinolone antibacterial agent which has enhanced in vitro antibacterial activity against Gram-positive bacteria, whilst retaining excellent activity against Gram negative bacteria. Without intending to be bound or limited by theory, gemifloxacin is believed to act via inhibition of bacterial topoisomerase II and IV. Gemifloxacin is highly selective for bacterial rather than human topoisomerase II.
EP 688772 discloses novel naphthyridine carboxylic acid derivatives, including gemifloxacin. WO 98/42705 discloses gemifloxacin mesylate and hydrates thereof including the sesquihydrate.
There still remains the need for improved methods of treating bacterial infections. In particular, infections caused by Psezudomonas aeruginosa continue to pose a therapeutic problem. In clinical practice, the combination of β-lactam antibiotic and aminoglycoside antibacterial agents has been shown to have an improved efficacy for the treatment of infections caused by P. aeruginosa. However, increased resistance of P. aeruginosa to aminoglycosides, coupled with their potential for nephrotoxicity, means there still remains the need for alternative treatments.
Other examples of infections for which improved methods of treatment are needed include those caused by Enterococcus faecalis, Staphylococcus saprophyticus, and Escherichia coli. 